SUM(1) General Commands Manual SUM(1)
sum - sum and count blocks in a file
Sum calculates and prints a 16-bit checksum for the named file, and
also prints the number of blocks in the file. It is typically used to
look for bad spots, or to validate a file communicated over some trans-
`Read error' is indistinuishable from end of file on most devices;
check the block count.